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        "\n# Parameter estimation using grid search with cross-validation\n\n\nThis examples shows how a classifier is optimized by cross-validation,\nwhich is done using the :class:`sklearn.model_selection.GridSearchCV` object\non a development set that comprises only half of the available labeled data.\n\nThe performance of the selected hyper-parameters and trained model is\nthen measured on a dedicated evaluation set that was not used during\nthe model selection step.\n\nMore details on tools available for model selection can be found in the\nsections on `cross_validation` and `grid_search`.\n\n\n"
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      "source": [
        "from sklearn import datasets\nfrom sklearn.model_selection import train_test_split\nfrom sklearn.model_selection import GridSearchCV\nfrom sklearn.metrics import classification_report\nfrom sklearn.svm import SVC\n\nprint(__doc__)\n\n# Loading the Digits dataset\ndigits = datasets.load_digits()\n\n# To apply an classifier on this data, we need to flatten the image, to\n# turn the data in a (samples, feature) matrix:\nn_samples = len(digits.images)\nX = digits.images.reshape((n_samples, -1))\ny = digits.target\n\n# Split the dataset in two equal parts\nX_train, X_test, y_train, y_test = train_test_split(\n    X, y, test_size=0.5, random_state=0)\n\n# Set the parameters by cross-validation\ntuned_parameters = [{'kernel': ['rbf'], 'gamma': [1e-3, 1e-4],\n                     'C': [1, 10, 100, 1000]},\n                    {'kernel': ['linear'], 'C': [1, 10, 100, 1000]}]\n\nscores = ['precision', 'recall']\n\nfor score in scores:\n    print(\"# Tuning hyper-parameters for %s\" % score)\n    print()\n\n    clf = GridSearchCV(\n        SVC(), tuned_parameters, scoring='%s_macro' % score\n    )\n    clf.fit(X_train, y_train)\n\n    print(\"Best parameters set found on development set:\")\n    print()\n    print(clf.best_params_)\n    print()\n    print(\"Grid scores on development set:\")\n    print()\n    means = clf.cv_results_['mean_test_score']\n    stds = clf.cv_results_['std_test_score']\n    for mean, std, params in zip(means, stds, clf.cv_results_['params']):\n        print(\"%0.3f (+/-%0.03f) for %r\"\n              % (mean, std * 2, params))\n    print()\n\n    print(\"Detailed classification report:\")\n    print()\n    print(\"The model is trained on the full development set.\")\n    print(\"The scores are computed on the full evaluation set.\")\n    print()\n    y_true, y_pred = y_test, clf.predict(X_test)\n    print(classification_report(y_true, y_pred))\n    print()\n\n# Note the problem is too easy: the hyperparameter plateau is too flat and the\n# output model is the same for precision and recall with ties in quality."
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